Switches in circuits alternate between activated or on states, where the switches are closed to conduct electric current from a source of the current to one or more loads, and deactivated or off states, where the switches are opened to prevent conduction of the electric current. These switches and/or the circuits that include the switches may encounter a variety of different short circuits in different locations of the circuits. Depending on the type and severity of the short circuit, the switch can be damaged or destroyed.
Some different types of short circuits require different protection schemes to prevent damage or destruction of the switch. Current protection devices such as fuses, gate drivers, or the like, may be insufficient to protect the switches when certain short circuits are encountered.
For example, some short circuits occur when the switch is initially activated or turned on. These short circuits occur relatively quickly and, in circuits where a relatively large amount of current is conducted, can damage or destroy the switch very rapidly. Fuses in these types of circuits may be unable to blow in time to prevent the large currents from damaging or destroying the switch.
Some other short circuits occur after the switch is closed and current is being conducted through the switch to the load. These short circuits can be dangerous to the switch in that the switch may be saturated with current and unable to merely switch off the conduction of the current. Abruptly eliminating or reducing the voltage used to control the switch (e.g., a gate voltage) can result in the switch being damaged or destroyed.
One known attempt at protecting switches from short circuits includes active clamping, which protects the switch from overvoltage at a short circuit turn-off. But, active clamping can require intensive tuning of an analog circuit and optimal performance for all operational conditions, which can be difficult, if not impossible, to achieve.